Electric-current controller.



L. BRADLEY.

ELECTRIC CURRENT CONTROLLER APPLICATION FKLED MAY 28.1909.

1,1 1 9.800. Patented Dec. 8. 1914 D 5 SHEETS SHEBT 1 5172272059115 V'5' fizz 622m 2 610706 1 Ly/M/(QB/UM/(y L. BRADLEY. ELECTRIC GummyULJNIROLLER AFPLIUATION FlLED MAYZKR H09.

1 ,1 1 9,800. Patented Dec.8,1914

5 SHEETS SHBET 3.

L. BRADLEY. ELECTRIC CURRENT CONTROLLER APPLICATION FILED MAY 23 li-i/1,119,800 Patented Dec 6, WU

GQHELIS JILL! L. BRADLEY. ELECTRIC CURRENT CONTROLLER APPLICATION FILEDHAY28,1909.

1, 1 1 9,800. Patented Dec. 8, 1914.

5 SHEETS-BHEET 5.

I l I l I l I I I I I I I I I I I 1 I I I I I I I Ly/zaeBmd/ sister.

ms]; STATEEE PATENT irjnim snantsir, or MUsKEeoN, MIcnIoANQ ssrenon ToALDQN-BRADLEY' centralize conronarzon" 'W scon'sm.

L all whom it may) concern; Be it known that ILLYNDE BRADLEY, a

citiz'en'of the United States of America, and a'resident of Muskegon,cmmty oflliuskegon, an dState of Michigai rhave invented anew and usefulImprovement in Electric- Current- Controller-sot which the following isa. specification.

My invention pertains to electric current controllers of the-type'ivhich comprises a combination of eleetric switches and variableresistances;

It relates more pairticulai-ly to devices in which the progression ofcontrol .ilever through a predetermined movement operates 'a switch tochange the cont-rolling circuits of fa power using de\-'ice,'arid of. aresistor, and e1 0- tovary 7 thewesistan'ee vvalue of therepresentinvention contemplates the employment of a resistancewarying devicen'hichth'e variations (if-resistance are secured by placing avsi-rzablepressure upon the resistor proper. Theresistanee medium '.'o rres stor of such resistance-varying de- 'yices, Imake preferably ofspecially treated carbon disks (as d sclosed in an application filed byHarry L. Bradley and myself, jointly. Serial 467. 332, filed December141:, 1908), hutl do not limit m self to this form of resist-or, asresistors of ordinary 'carhon such as are disclosed in my Patent '815317,-h'iarcn 13, 1906, or of other mate rials, may be employed. Insteadof the resister being in the forni rfidisks, 1 may employ other shapes,such'as granular, spherical or other forms, in anyof which cases Iconfine theresistor in a suitable manner in retainer of form such as tomake-it Oder suitable hath forthe current to whe varied and to hold itin readiness for :the required comoression.

My irnoroved current controller comprises novel means for supp'ortingandfor varying the pressure upon the compressible resistor form ng thevariable-resistancepart of a current controller,ai id novel electricaland mechanical features involVed-ilkithe arrange- ELECTRIC-CURRENTCONTROLLER.

Specification of Letters Patent. 4

and improved details-0f the .oireui Patented Dee. 8;,1914.Applicationfiled Kay 2s, 1909. Serial :10. 438,850.

inent and adapted to assist the functions of such means. One'featu-re.of such amarrangement involves the sustaining-0i the resister directly 4upen the controllinglei-"er..-

Another feature is the arrangement of the various parts in relation toeachother whereby the saine'motion of the controlli'ng 1 lever whichaccomplishes the compression or deeomoression of the -lf61Si20!'-, -also will ac compli'sh the desired--:circuit changes and other functionsof the controller.

.the mounting of the resistorcontainer. upon I the operating erii1 ,j,by1e- ;r no \7ement1 of which arm the resistor., s compressed.ordecompressed and by .the; '1n oi7 merit-of which also gthe circuitchanges-are c'complished. Under. thejmoven'ie'nt' of: -.t his ,'arm-;f=therefore, the resistor with itsi i'a-diating surfaces is moved back andforth-through the airy; thus aiding in)- the rapid ,jclispersionof theheat generated within thejr'esistor;

()ther; featuresl of my improved current controllers are-high insulationbetween jthe Current-carryingparts of the -controller and the mountingbase o'r iram'e of the device,

mg switch. I particulerly'guar the flow of electric current throughhighly heated insulation members. Besides a'ncvel arrangement of thecircuitchanging switch parts nrovide improvements in .they briiislijdevices. o

Figure 1 shows front view-of an.'el ect-r i c current controllerconstructed in accord:

ance with the principles of my-inventionf Fig. 2 shows a. similar VIEWwith divers brake magnet connected in shunt.

full s eed. Fig. 5 shows circuit connections when a series motor isbeing started in reverse direction. Fig. 6 shows circuit connectionswith a series motor having an electric Figs. 7, 8, 9 and show details ofmy impro ed brush and brush. holder for the circuit changing switch.Fig. 7 shows view of the single brush, looking at its end. Fig. 8

shows a view of the double brush from the same direction. Fig. 9 shows aside view of the device of Fig. 8, and Fig. 10 shows a sectional view ofsame on the line 10 of Fig. 8. Fig. 11 shows section of Fig. '2 on line77. Fig. 12 shows a detail, and Fig. 13 a modification thereof.

Referring toFig. 1, a frame 1 supports an insulating slab "2 upon whichdivers'conductingcontact (pieces for the switching circuits Upon. theframe 1 is mounted by four bolts,- 1'.', 1", 1", 1",

are arrange a subframe 1 having insulating WfiSl'lGIS and bushings.

- mounting the operating lever 4 audits sup- Upon subframe 1" is tubularshaft 3, lined with insulation 3 and fixed by set screw 3, which shaftsupports pivotally the operating lever 4 carrying a resistance unit 5.

Tubular sleeve 4 is an integral part of arm 4. Set collar 3 set by screw3 holds l on 3 and is of cup shape to prevent the lubricating oilbetween 4 and 3 from working out readily to the end of tube 3 and to thecontained conductors. The object of thus ported resistance unit 5 uponan insulated subfra'me is to secure an insulation separation of the mainframe from the resistance unit so located that the-insulation will notbe subjected to great heat. Most insulators" become partial conductorsas their temperature rises, and for this reason the insulation of theresistance unit -5 might at times permit some flow of current to themain frame 1 were the main frame to become grounded and were the pathfor'such current not interrupted by the provision of the auxiliary 4insulation surrounding the bolts-1" supcarries single brush 6 and doublebrush 7 for controlling the switching circuits of the currentcontroller. and in addition this operating arm carries the resistanceunit 5.

The operating arm 4 carries upon itself the- 'vaiiable resistance device5, and this dethere'fore partakes of the lateral move- Jlient of thearm; its relation with the arm ai d'its associated parts being such thatas erated therein. By mounting this unit upon the operating lever Iattain the advantage.

of greatly assisting'in the dissipation of this heat by the consequentmovement of this unit through the air; this dissipation of heat alsobeing assisted the radiating fins or flanges 5 which give increasedradiating surface to the tube containing the variable resistance medium.Such controllers are largely used in mills or factories under conditionswhere-dust is likely toaccumulate upon them. An additional advantage,which accrues from the mounting of the resistor unit directly'upon thearm, is that at every operation of the arm there is such a morement andjarring of the unit as to tend to shake off the dust and thus preventsuch an accumulation as would j interfere with its heatradiatingproperties.

A further advantage, secured by mounting the resistor in front of thecontroller panel rather than on its rear, is in the matter of enforcedprominence, resulting in its greater accessibility and in a decrease infire hazard in cases where controllers are mounted in proximity to 'aninflammable wall. Furthermore,- this position assures a free circulationof air about the unit, which is not so readily obtainable where theresistance units are mounted back of the controller panel close to awall and particularly ivhere they are so mounted close to the floor me.The controller arm 4 carries upon it parts of the .switching device-forchanging the circuits of the resistor and of the controlledcircuit-using device. Brushes 6 and 7 are contact members of the circuitchanging switch, and conductors 28 and 32 leading to those parts alsoare carried by the arm An improvementin thecircuit-controlling switch isfound in the construction of brush holders designed to be carried by thearm t. The brush holders are two in number, the upper one carryingdouble brush 7 and the lower one carrying single brush 6. These brushholders and their brushes are shown in Figs. 7, 8, 9 and 10. Each brushholder consists substantially of a single base structural part holdinthe brushes movably in proper position, the base part carrying alsoterminal binding posts for the leadingin wires, and a conductingconnection being made to the brushes by a flexible conductor. The brushbase partbO is illustrated in Figs. 8, 9 and 10, and comprises a fiatplatformlike structure having four lugs 61 for four mounting screws.Projecting downwardly from the platform portion of the base are tubularparts 62' which hold slidahiy the hrusnes 63. j Projecting upwardlyfromthe the br shencl is'secil'red by drivepin 66. 15-Sp1ting 68 isattached at. one end to the fiber lpin anrl atthe other end to aselected one of" the serews6'7 in the liig '65. These screws.are'pleced. at difi'erent heights and the ten sion of the spring 68maybe determined by go the seleetion exercised-among the screws 67' illwe stretched. Thescrews 67,' in view f theirvarying heights; alsoprovide. for taking up thewear of the .brnsh tips 63'. sthe l'rrnshwesrs shorter, the spring 68 is drone -i [rush The device of Fig 7,e:irrying the -"e-currents;particularly when the v h'roughn motorisftirst closed and, e theispring 68 .is-heavily shunted not 510" i byQthe handfeonciuetois'fil 'but also by -tween parts and 62, yet'ncurientto heat thev spring 68 mighttlms damaging'its' temper To avoidnah The brush hoiders'nre mounts jich. position that the shaft 33 15 suball? perpendieuiar to the plane of the the fixed elements of the switchefsen G3 and such eles a complete resist-- mdiziting element, which neewhen snb e platform-portion of the base are theilugs 64,

A'fiber'pin 66 is inserted transversely in .With' reference to theirheight, thus deterning the length towhich the spring 62} to thenextlower screw. Tl1e en rushholrler.is nsnlated from the arm snlat ngWashers and bush ngs at the un eated and are designatez i as v,tlonlile'Ig-le hrush 6, isfsimilar in all essential reets,-l)ut1s modifiedndes'igo to carry but" ts bri sh brushes are. likely, to carry:

ihility make the pin 66 (if-insulate.

of the fixed conduct ng elez'nents of the irselr respeetiveiy.

upon abutment 10. Yoke 9 am abutment 10 are rigid parts upon theoperating arm 4', preferably being all one casting, while carriage 8ismounteii slidably the slot of yoke 11, so thatcarriag'e 8 may move toward abutment l 'and thus compress resistance unit 5 between the twoparts8 and 10. Carriage 8is-pivotally .atta'ehed by shaft'8 to the castframe 12, which iszin the form of two rods; one behind; theother asviewed in Fig. 2, the rods connected at the bottom and'at 12". ByshaftlZ, 'set by screw 12*, the frame'lfz' is pivoted to rod'13.

Frame 12 passes slidahly through the'guide 1 upon the subfra-me 1'.Upon'the arm- 4 is a-transverse arm 15, Which-in"? is shown broken awayto reveal the mechanismat the back thereof. twostuds 16 and 17 which areengaged by- The arm carries hook ended transverseitrms-18 and 19*u'ponthe rod 13. A toggle mee hanismn'ow- 'is' dis-' cernible having itsextreme pivots at l2gand the axis '3 of: the pivo ted'a'rm ls-and havingits intermediate pivot at 16" or '17 dependng npon whether the -*0per21ting';,-arm 4 "moves to right or left,'respeetivelyx'fThe 7 brokenlines on and b b'.-=- a're"eonstruetion lines indlieatingthe'inechmiioal elements of the toggle movements jhstides'bribecl;'VYhen the operating leverkt is moved-to t he'right,

and lifts the yokeistmitim md-13,-wh n i'ct'in'g throiigh pivot li'iliifts sliding frame '12 and carriage '8, compressing. the-'res1stanee nit 5. This compression vil'l-e'ontinue and increase asthe'operatingarm is moved else that the ratio'of powerqconversion be-'co'rnes one of greatersineqiialitieas tliefp res- 5-. becomes 105' sureupon the'resistane innit H greater. [At the'beginning ofthezr'novementof the operating" arm 4 to 'tl'l iij-Iilglli}; hook L9 is lifted fromthe studj1'7. Upon" the movement of tl1e= operating arm 4 to theieft, asimilar mechanical,setion'oecnrs' in volving the stud 17 and hooker atthe center and at the two ends of the This device holds the 22 13. "Thefunction of the roller nn illiCl'I when thus modified is niways to.

ieturn the arm 4 to its middle position whenever the operating handle orropes are released by the operator.

In order that the conductors 28, 31 and 39 (see Fig. 6) which lead toterminals car ried by the operating arm lmay be subjected to a minimumamount of bending, I mount the arm 4 upon the insulation-lined tubularshaft 3 and bring the conductors 31 and 28 (and 39 when needed) throughsaid shaft, the location of the conductors thus approximating the axisof movement of the operating lever 4. By this means the flexibleconductors are subjected to little bending other than a twist through avery small angle.

The resistance unit 5 is carried by the plate 50. Threaded studs 51, 52engage carrings 8 rotatably and plates 50 and 53 are mounted upon thestuds, the coiled compression spring 57 being'placed between them. Plate53 is threaded upon rotatable studs 51 and 52 and is held locked by nuts5-l and 55. Thus the pressure of carriage 8 is transmitted through studs51 and 52 to plate 53 thence through spring 57 to the loosely slidingplate 50 which carries the resistance unit 5'directly by engagement withthe flange 56 which is rigidly mounted upon the resistance unit 5. Theresistance unit 5 projects through olates 5O and.5 l and also throughcarriage 8 to secure and maintain the alinement of all, parts. Theadjustment afforded by studs 51 and 52 provides for any variation in thelength of the resistance unit 5; it provides also for an ad justment ofthe distance between 50 and 10 whereby the beginning of pressure uponthe resistance unit 5 may be caused to occur sooner or later in themovement of the arm 4 from its central position; it provides also forregulating to any predetermined degree the maximum pressure andtherefore the minimum resistance which may be attained for theresistance unit- 5 when the lever t is in either of its extremepositions.

The circuits proposed for the specific electric current controllerherein illustrated when used to controla series motor are shown in Figs.3, 4, 5 and (3, and may be un derstood from them. lVhen the operatingarm 4 is in its middle position, the brushes rest upon the threeisolated central points in a. vertical line at and all circuits areopen. At the first movement of the operating arm 4 to the right thecircuits of Fig. 3 are obtained. Current assumed to be re ceivcd fromconductor 2i passes through switch contacts 25, 2G, and 2?, brush (3,conductor 28, armature conductor 30, conductor 31, resistor 5, conductor32, brush 7, switch elements and 34, conductor 35 and field winding 36to return conductor 37. As the movement of the operating lever 4continues toward the right, the circuits described are not changed, butthe resistance of the resistance unit 5 is decreased continuously untilthe operating lever reaches its extreme position, at which time thebrushesfi and 7 are at the extreme right and brush 7 makes contact with.switch element 38. By this contact the resistance unit 5 is shunted andthe full potential of the power mains is given to, the m otor. Thiscondition is illustrated in Fig. 4.

- In Fig. 5 the condition of starting in reverse direction is shown. Inthe circuit of this figure, current flows through 24. 25, as, 7, as, 5,a1, 30, 29, 2s, 34, 35, so, 37, thus passing through the armature in theopposite direction and through the field in the same direction,reversing the direction of the rotation of the armature.

In Fig. 6 are shown the circuits suitable for the device of Figs. 1 and2, when used as a motor controller for a series motor having an electricbrake magnet 40 connected in shunt. In this arrangement of circuits, thecircuits are open when the controller lever l is in its middle position,while in any other position of the controlling lever the armature is inseries with the resistance unit, the brake magnet is in shunt of thearmatureand-resistance combination, and the field is in series with all.When the arm it isin either of its extreme posi-. tions the resistanceunit 5 is short-circuited. The brake magnet 40 therefore is subjected atall times to the drop of potential across the armature 29 and resistanceunit 5, this drop of potential being sufiicient to operate the magnet toremove the brake at all times. Circuit may be traced through 37, 36, 35,34, on, '7, 32, 5, 29, (5 and 29 being shunted by 40, 28, 6, 27, '26,25, 24. lVhen starting in reverse direction, the circuit is through 37,36, 3 6, 28, 29, 5, ('29 and 5 being shunted by 40,) 32, 7, 26, 25, 24.

Having thus described my invention what l claim as new, and desire tosecure by United States Letters Patent is:

1. In an electric current controller, the combination of a resistor; aswitch for bringing said resistor into and out of an electric circuit;and an operating lever for said switch, said resistor being mdunted uponsaid operating lever and movable with said lever.

2. In an electric current controller, an operating lever; an electricswitch, the brushes forming a part of said switch being carried uponsaid lever; conductors connect ing to said brushes; and a tubular shaftupon which said operating lever is mounted and through which saidconductors pass.

3. In an electric current controller, the combination of a resistorwhose resistance is variable by pressure; an operating lever upon whichsaid resistor is mounted; an

abutment upon said lever and engaging'one end oi said resistor; and amovable member upon said lever and engaging the other end of saidresistor.

4. In an electric current controller. the con'ibination of an operatinglever; a resistor Whose resistance is variable by pressure, saidresistor being mounted upon and carried by said lever; means for placinga variable pressure upon one end of said resistor and means upon saidlever for retaining the other end of said resistor, said retaining meanscomprising a yoke through which said resistor passes slidably and afixed abutment against which said resistor may be pressed.

5). In an electric current controller, the combination of a lever, aresistor mounted upon said lever and movable therewith in. such manneras to assist in the ventilation of said resistor;

6. In an electric current controller. the combination of a compressiblevariable re sister; coi'npression means for said resistor: saidcompression means comprising an op:- eratiug lever and other levers. andsaid resistor being mounted upon said operating lever and movabletherewith.

7. In an electric current controller. the combination of a coi'n'iressibie variable resistor: a moving lever having a fixed abutment andguide adiacent to said fixed abutment and a movable c2 rriage positionedonposite said abutment and guide. said resis" tor parsing through saidguide and being re ained between the said carriage and said abutment:and means for mining sa d can riale toward and from said abutment whensaid lever is moved.

8. In an electric current controller. a coinpressible variable resistor:an abutn'ient therefor; a carriage therefor movable tr nard and fromsaid abutment: a pair ol' lates interposed between sa d carriage andsaid res stor. one of said plates engaging said carriage adjustabl v:and a spring between said plates \vl'ierebv pr sure exerted lvv saidcarriage upon said i'-: stor is trans mitted onl) through said S 'HlnQf.

9. In an ele t i current mutrollcr. a ent pressiblc variable aster: analiulnu-nt therefor: a carriage tiierel m' movable t ward and from saidabutment: a ",llil of iilatcr iiiter irsacd between sa mirriao' .lllllsaid 'stor. n of said plates eugsgin! I wag ailir tahlvz and a sprint bnlicrebv pressure eri rio l moo said resistor is lliill-i m said spii,wi l it pair in form and said olales "1\% bring guri'oraljed and said oru ing, through said plates 3 or \ilx-rcov 'thc a inenient oi the sistedand maintained.

clecir'ir curreir controller, a trainer 2 su'ofranie; insulating)"mountings for said suhframc and sustaining: it upon said main frame: anda heat radiatii'ig element upon said subt'raine. said insulatingmountings being situated remotely from said radiating: element.

11. In an electric current rtmtroller. a main i'raine: a subl rai; and aresistor; said resistor beiue; doublv insulated from said main framefirst by insulation between said resistor and said sublrame and secondby insulation between said subframe and said main frame.

12. In an electric current controller, a main frame; a snbtrame; acontrolling lever mounted upon said subtrame: and a resistor mountedupon said lever; said resistor being doubly insulated from said mainframe first by insulation between said resistor and said srhtraine, andsecond by insulation between subtranie and said main frame.

115. In an electric current controller. a controiiing lever; 21compressible resistor lliOlifltQClllPGIl said lever; a guide yoke and afixed abutment for one end of said resistor and made integrally with thebody of said lever; and means movable upon said lever for supporting theother end of said resistor.

.le'i. In an electric current controller, a controlling lever; acompressible resistor mounted upon said lever; a guide yoke and afixcdabutment for one end of said resistor and made integrallv with the bodvof said le er; means movable upon said lever for supoorting' the otherend of said resistor. a guide yoke upon said lever for said movablemeans, said guide voke being also formed integrally with the body ofsaid lever.

15. In an electric current controller. a roi'nbination of an operatinglever: a resistor whose resistance is variable by pre sure. saidresistor being mounted upon and carried bv d lever: means for placing avariable ll't .nre upon om end of said resistor and means upon said leer for retaining: the other end of said res stor. said retaining meanscomprising a vo v'e thro gh vhii'h said resistor passe" slidiiiilv and afixed abutment against W 'h said rr "star inn; be pressed. said \filie.fixed ab tment and li er be ng formed inteerallv.

'16. In an electric current controller. a con trolling lever: a coniprissililc resistance unit thereupon; fixed means upon said lever forholding one end oi said compressible re sistai'ice unit: a movablecarriage upon said lever for hold ng the other end of said re sistanceunit; and a toggle for moving: said movable means to compress saidresistance unit.

17. In an electric current controller a controlling lover; acompressible resistance unit thereupon: fixed means upon said lever forholding one end of said compressible re sistance unit; a movablecarriage upon said lever for holding the other end of said re'movable'means to compress said resistance unit, said lever forming astructural member of said toggle.

18. In an electric current controller, a controlling lever; acompressible resistance unit thereupon; fixed means upon said lever forholding one end of said compressible resistance unit; a movable carriageupon said lever for holding the other end of said resistance unit; and atoggle for moving said movable means to compress said resistance unit.saidlever forming a structural member of said toggle and said togglebeing operated by said lever.

19. In an electric current controller, an operating arm; a toggle ofwhich said operating arm in part forms a structural memher; acompressible resistance unit carried upon said arm; and means forvarying the pressure upon said resistance unit by the action of saidtoggle when said arm is moved. 20. In an electric currentcontroller. acon- .trolling lever; a compressible resistance unit thereupon; fixedmeans upon said lever for holding one end of said compressibleresistance unit; a movable carriage upon said lever for holding theother end of said resistance unit; and means for adiusting the normaldistance between said fixed means and said movable carriage.

21; In an electric current controller. a controlling lever; acompressible resistance unit thereupon; fixed means upon said lever forholding one end of said compressible resistance unit: a movable carriageupon said lever for holding the other end of said resistance unitrandmeans for adiusting the normal distance between said fixed means andsaid movable carriage. said adjusting means comprising screw studsengaging said carriage and carrying parts which in turn supportthe'resistance unit.

22. In an electric current controller, a movable pivoted arm; conductorterminal devices upon said arm: a tubular shaft upon which said arm ispivoted; an insulating lining for said shaft; and conductors pass ingthrough said shaft and through said insulating lining and connecting atone end to the said terminals.

23. In an electric current controller, a fixed tubular shaft: electricalconductors passing through said tubular shaft: a movable part sleevedupon said shaft: and a collar holding said part upon said shaft, saidcollar being concave on the face near said movable part.

24. In an electric current controller, a fixed tubular shaft, electricalconductors passing through said tubular shaft; :1 mov able part slee edupon said shaft; and a cup-shaped element being at the same time arestraining element to hold said movable 'partupon said shaft and an oilshield fo'r said conductors.

25. In an electric current controller, a frame; a tubular shaft; amovable part, said movable part being supported uponsaid frame pivotallyby means of said tubular shaft,- electrical conductors passing throughsaid tubular shaft; and a cup-shaped element forming at the same time anoil shield for said conductors and a means for mainrest; pulleysattached to said frame work structure; and a rope attached to said armand passing through saidpullevs wherebv, by power applied through saidrope, said arm mav be moved from its position of rest, and said springcompressed said spring operating subsequently to restore said arm to itsposition of rest when the rope is released.

27. In an electric current controller, a framework structure; acontroller arm iournaled upon said structure; a resistor mounted uponsaid controller arm and carried by said arm and ventilated to dissipateheat by the movement of said arm; a track mt'illluzl attached to saidstructure; a roller upon said arm and pressing upon sui'l track; .1spring carried upon said arm and press ng said rollev'e gamst saidtrack, said track being so connected that the spring of i'ilL roller iscompressed when said operating arm is moved from its normal position ofrest; pulleys attached to said frame work structure; and a rope attachedto said arm and passing through said pullevs \vherebv, by power appliedthrough sa d rope. said arm mav be moved from its position of rest, andsaid spring compressed. sazd spring operating subsequently to restore s:id mm to its position of rest when the rope is released.

28. In an electric current controller, a tubular shaft; a mo able oillubricated part journaled upon said shaft: electrical conductors passingthrough said shaft; and an oil shield for said conductors.

29. In an electric current controller a. tubular shaft; a movableoil-lubricated part journaled upon said shaft; electric conductorspassing through said shaft: and an oil shield for said conductors, andbeing at the same time means for holding said movable part upon saidshaft.

isupported upon said sub-frame, said main frame carrying means ofattachment to wall, floor, or other support.

31. In an electric currentcontroller, :1 variabie resistance;compression means comprising an operating lever and other levers, andsand resistance being nmunted upon said operating lever and. movableiii-ai-ewith.

Signed by me at Chicago, county of Cook, and State of Illinois, in thepresence of two 15 Witnesses.

LYNDE BRADLEY. Witnesses DAVID S. HULFISH, HARRIET L. SMITH.

